Recuperative form of thermal-catalytic incinerator

ABSTRACT

A special form of incinerator design provides for either a catalytic or thermal operation, or simultaneous conversions, in that burner means is provided for initiating catalytic oxidation or for discharging hot combustion gases into an elongated central combustion section to thermally oxidize the combustibles in the fume stream. The invention involves an elongated outer housing, internal cylindrical-form partitioning spaced inwardly thereof to define an annular gas flow space therein, an internal combustion section, burner means at one end of the housing with fume inlet means into said housing to the combustion section, gas pervious catalyst in at least a peripheral portion of the cylindrical-form partitioning, open passageway means at one face of the catalyst to permit the fume stream being treated to pass radially through the catalyst, and treated gas outlet means from the opposing face of the latter.

United States Patent Tabak *Aug. 5, 1975 Primary Examiner-James H.Tayman, Jr. Attorney, Agent, or Firm-James R. Hoatson, Jr.;

[75] Inventor: Fernando Tabak, Norwalk, Conn. Philip T gg William H.Page H [73] Assignee: Universal Oil Products Company,

Des Plaines, Ill. [57] ABSTRACT 1 Notice: The Portion of the term ofthis A special form of incinerator design provides for ei- Patem f q fto 1991 ther a catalytic or thennal operation, or simultaneous has beendlsclalmedconversions, in that burner means is provided for initi- [22]Filed; 26, 1973 ating catalytic oxidation or for discharging hotcombustion gases into an elongated central combustion [21] PP N054282640 section to thermally oxidize the combustibles in the RelatedAppficafion Data fume stream. The invention involves an elongated l 63]Continuatiomimpan of Sen N0 267328, June 29 outer housmg, internalcyllndrlcal-form partltlomng 1972 Pm No. 3 806 322' spaced inwardlythereof to define an annular gas flow space therein, an internalcombustion section, burner 52 us. 01 23/277 c; 23/288 R; 110/8 A; means3 end of the housing i inlet 423/210; 431/5 means into sa1d housing tothe cornbustlon sectlon, gas 51 Int. Cl. F23g 7/06; B01 j 9/04 Catalyst1 Perlpheral 58 Field of Search 23/284, 288 R, 277 c; cylmdncal'formpammnmg' OPen Passageway means 60/299, 350; I 10/8 A; 431/5; 423/210 atone face of the catalyst to perm1t the fume stream being treated to passradially through the catalyst, and l 56] References Cited treated gasoutlet means from the opposing face of the UNITED STATES PATENTS latter3,806,322 4/1974 Tabak 23/288 F 5 Claims, 4 Drawing Figures 1 0 I l I Il Fuel IT Treated Gas our/er.

PATENTEDAUB 51915 Figure i: i Fuel 1 /5 Treated 60s Our/e1 Figure 3RECUPERATIVE FORM OF THERMAL-CATALYTIC INCINERATOR This application is acontinuation-impart of my earlier application, Ser. No. 267,328, filedJune 29, 1972, now Pat. No. 3,806,322.

The present invention relates to a special form of fume incineratorwhich provides for either a thermal or catalytic type of operation, orboth at the same time. An improved and preferred embodiment of thepresent invention also provides for a heat recuperative operation byhaving the incoming fume stream pass through an annular form heatexchange zone in heat exchange relationship with the resulting purifiedhigh temperature discharge stream.

It is recognized that many forms of thermal and catalytic incineratorshave been designed and are in commercial usage to effect the oxidationand purification of noxious waste gas streams; however, the presentdesign provides a compact and novel design and arrangement which permitsthe insertion, or removal, of catalyst elements to switch from one typeof operation to the other. In fact, in the event that the catalyst operation for some reason fails to perform properly, the burner means can bereadily operated at a sufficiently high temperature to have a thermalincinerator type operation while the catalyst elements remain in placeor are removed.

A preferred form of incineration unit will also use a 100% secondary airburner, such that no primary air need be supplied, to thereby provide ahigh efficiency operation, As for the burner means and the gas flowarrangements, the present design is related to that disclosed in myearlier application, Ser. No. 267,328, and also somewhat related to mynow issued US. Pat. No. 3,549,333; however, in this instance, the innercylindrical partitioning is comprised in part of gas pervious catalystmeans such that a preheated gas stream can flow radially through thecatalyst and be catalytically oxidized to remove noxious components. Thecatalyst may be a thin bed of impregnated refractory particles orpellets; a catalytic agent impregnated onto a honeycomb" type ceramicsupport; or, preferably, will be of an all-metal construction such asmay be provided by catalytically coated ribbon or wire in mat formbetween retaining screens.

Actually, it may be considered a principal object of the presentinvention to provide a thermal-catalytic fume incinerator unit withburner means and catalyst elements being suitably placed such that theunit can readily operate either thermally or catalytically without anynecessary modification.

As another object of the improved design, there is provided anarrangement where the fume stream will be in heat recuperative, heatexchange relationship with the oxidized stream and also be subjected toan elongated passage through the burner section and catalyst means toprovide a greater overall length of combustion section for reaping thebenefits of time, temperature and turbulence in carrying out the fumeincineration.

In a broad aspect. the present invention provides a thermal-catalyticfume incineration unit, which comprises in combination, an elongatedouter housing, internal cylindrical-form partitioning spaced inwardlyfrom the wall of said housing and extending for at least a portion ofthe internal length thereof to define an annular gas flow spacetherebetween and an internal combustion section, burner means positionedat the end of said housing and means to discharge hot burner gasesaxially into said combustion section, fume inlet means into said housingand to said combustion section with passageway means to the latterentirely surrounding said means discharging the hot burner gases, gaspervious catalyst means in at least a peripheral portion of thedownstream section of said cylindrical-form partitioning, and openpassageway means to one face of the catalyst means from the combustionsection whereby the fume stream being treated may be passed in a radialtype flow through said catalyst means, and treated gas outlet means fromthe opposing face of the latter and from said housing.

In a more specific aspect, the present invention provides a recuperativeform of fum'e incineration unit, which comprises in combination, anelongated outer housing, inner partitioning spaced from the outerhousing and terminating short of one end of said housing to provide anexternal annular heat exchange section and a central gas combustionsection, a transverse partition positioned across the internal end ofsaid inner partitioning to provide a preheated gas inlet section in theend of said housing and an end closure for said annular heat exchangesection, a burner means connective with the end of said housing at thepreheated gas inlet section and burner gas passageway means therefromfor discharging of hot flames and gases into said combustion section,additional transverse partitioning that is positioned a spaced distancefrom the other end of said housing to provide a gas inlet section and asecond end closure for said annular heat exchange section, a pluralityof open-ended tubular members extending between and through saidtransversely positioned partitions to define inlet gas passageway meansthrough said heat exchange section from said gas inlet section to saidpreheated gas section, open passageway means from the latter section tosaid central gas combustion section which encompasses said burner gaspassageway means, gas permeable catalyst means positioned in at least adownstream portion of said inner partitioning to thereby permitcatalyst-gas contact and gas flow into said heat exchange section fromsaid combustion section, a gas stream inlet to said housing and to saidgas inlet section, and a treated gas outlet from said heat exchangesection and from said housing.

As set forth briefly before, the catalyst elements or catalyst means maycomprise an all-metal construction such as high temperature resistantwire or ribbon plated or otherwise coated with platinum, palladium, orother active metal, whereby there is an active oxidizing catalyst toeffect the incineration of combustible fumes in the gas stream to betreated. Reference may be made to US. Pat. Nos. 2,685,742 and 2,720,494.Alternatively, the catalyst section may comprise one or more elementsutilizing coated refractory pills or other subdivided particles whichhavea catalytic coating suitable to effect the desired oxidationreactions. For example, spherical-form alumina particles may beimpregnated or otherwise coated with a suitable oxidizing catalyst agentand such particles retained between perforate screens so that there ispermeability for the radial inward or outward flow of the gas streampassing from the inlet and burner zones of the incinerator unit.

Reference to the accompanying drawing and the following descriptionthereof will serve to illustrate various features and advantages of thepresent invention as well as point out specific aspects of constructionto obtain the desired optional thermal or catalytic fume incinerationoperations as well as heat recuperation.

FIG. 1 of the drawing is a longitudinal sectional elevational view ofone embodiment of the present thermal-catalytic fume incineration unit.

FIG. 2 of the drawing shows a partial cross-sectional view, as indicatedby the line 2-2 in FIG. 1.

FIG. 3 of the drawing is a diagrammatic partial longitudinal sectionalview indicating radial outward flow through a catalyst sectionpositioned primarily downstream in the combustion zone.

FIG. 4 of the drawing is also a partial longitudinal sectional viewthrough an incinerator unit where there is radial inward flow throughthe catalyst section and also a modification in the gas outletpositioning.

Referring now particularly to the FIGS. 1 and 2 of the drawing, there isshown an outer shell or housing 1 arranged to have a contaminated gasstream inlet 2 connective with an internal gas distribution section 3,which in turn, passes the stream through a plurality of spacedopen-ended tubular members 4 within a heat exchange section 5,hereinafter described in further detail. Positioned across the inlet endof the housing is a partitioning sheet or tube sheet 6 which defines theinlet section 3 as well as an end for the heat exchange section 5. Atthe opposing end of the housing 1, there is a second transversepartitioning sheet 7, also serving as a tube sheet, which defines theopposing end of the heat exchange section as well as provide a preheatedgas section 8 for the distribution of the heated fume stream into thecombustion zone 11 of the incinerator unit.

Extending into and through a central portion of the preheated gassection 8 is a burner means defined by a perforated frusta-conicalmember 9 and a fuel inlet line 10. It is to be understood that varioustypes of burner means may be utilized in connection with the presentform of incinerator unit; however, a preferred type of burner will be ofthe 100% secondary air type having only fuel introduced into theinterior of the burner cone means 9 from line 10 and the air, or oxygencontent, required to sustain combustion will be supplied by way of thecontaminated air stream entering the incinerator unit from inlet means 2and the heat exchange tubes 4. Preferably the cone means 9 will have aplurality of holes in order to permit air and gases into the interiorthereof and mix with the fuel being injected by way of line 10. At thesame time, there will be passageway means around burner cone means 9 toprovide for the flow of the entire fume stream into an internallypositioned combustion zone 11.

In accordance with the present invention, an interiorly positionedcylindrical-form partitioning wall is provided longitudinally at aspaced distance from housing 1 so as to define the heat exchange section5 as well as the internal combustion section 11. Such wall may becomprised primarily of one or more catalyst sections 12, such as shownin the drawing. along with a short cylindrical end portion 13 or,alternatively, as will be more fully explained hereinafter, there may bea longer non-perforate wall section 13 in combination with one or morecatalyst sections which are of more shorter lengths. Various types ofcatalyst elements may be utilized in connectionwith the presentincinerator unit as hereinbefore noted: however, the one or morecatalyst sections will be of a gas pervious nature such that the fumestream and hot combustion gases leaving burner cone 9 and entering theaxial portion of the unit can pass in an outward radial flow throughcatalyst means 12 into the encompassing heat exchange section 5. In thepresent diagrammatic drawing, catalyst element(s) 12 are supported atthe burner end from suitable flange means 14 from wall cylindricalsection 13 as well as from transverse tube sheet 6 at the opposing endof the incinerator unit. Support angles 15 or other suitable means thatmay be attached to partitioning wall 6 can be provided to removably holdthe end of the catalyst unit. Although no detail is shown, the catalyst12 is preferably constructed and mounted to be removable by utilizing aplurality of cylinder-like sections or a plurality of arcuate-likelongitudinal pieces held by suitable support means, such that thecatalyst can be removed or replaced in the event that it needsreplacement or regeneration. Also, there may be an operation where thepresent form of convertible incinerator unit will be entirely thermalsuch that all or a part of the catalyst sections may be removed or, ifdesired, replaced with perforate partitioning to in turn permit athermally incinerated fume stream to pass radially outwardly throughsuch partitioning into the heat exchange section 5 and then bedischarged from the housing by way of outlet means 16.

While the present incinerator unit will normally operate eitherthermally or catalytically, it is to be noted that the presentembodiment also lends itself to a combination type of operation or thefume stream. Thus, the fumes can be primarily thermally converted fromhot combustion gases supplied by the fuel and burner means at thepreheated gas inlet end of the unit, and then there can be a furthercombustion and clean-up of the fume stream by the second stage catalyticcontact of such stream prior to its leaving the incinerator unit. Wherethe unit is being operated primarily as a catalytic incinerator, theburner means will normally supply only sufficient heat input to insurethat the contaminated gas stream is brought up to an oxidizingtemperature for catalytic incineration as it passes through the one ormore elements 12. Conversely, where the unit is operating primarily as athermal incineratorthen the burner means will supply sufficient fuel,flame, and hot combustion gases to insure substantially completeincineration of oxidizable components in the contaminated air stream. Inthe latter instance, the catalyst elements 12 will normally have beenremoved from the incinerator although, as heretofore noted, suchelements may be left in the unit.

As heretofore noted, various types of catalyst support means, as well ascatalyst element configurations, may be utilized to form the catalystsection in the cylindrical-form partitioning wall as well as theseparating wall means between combustion zone 11 and heat annularformheat exchange section 5. Also, various types of baffling and tubesupport means may be utilized in the latter section and it is notintended to limit the present invention to any one type of construction.In the present instance, there is diagrammatically indicated a bafflemember 17.which will assist in providing turbulent flow and thechanneling of the hot combustion gases around tubular members 4 afterthe outward radial gas flow through catalyst means 12.

In FIG. 3 of the drawing, there is indicated a slight modification tothe incinerator unit design and construction in that a longer internalnon-perforate partitioning section 13 is provided at the burner end orfume inlet end to an internal combustion section 11' and a shorteroverall length is provided for catalyst means 12 at the downstream endof the partitioning wall defining the wall means between combustion zone11' and a heat exchange section 5'. There is also indicated theplacement of a transverse partitioning member 18 within combustionsection 11' so that hot flames and combustion gases will necessarily becaused to pass therearound and through an annular space 19 prior toreaching a downstream combustion section 11 prior to the radial outwardflow of gases into the annular heat exchange section 5. There is furtherindicated in the embodiment of FIG. 3, the placement of a treated gasstream outlet means 16' adjacent the downstream end of heat exchangesection 5 and tube plate 7' such that there is a resulting reversal offlow in the hot treated gas stream with respect to gas flow withincombustion zone 11. The fume inlet end to the incinerator unit of FIG. 3may well be similar to that shown in FIG. 1 of the drawing or,alternatively, may be into the side of housing to communicate with theinternal gas distribution section.

In still another modification of the present form of incinerator unit,reference may be made to FIG. 4 of the drawing where an incineratorhousing 20 is provided with only partial longitudinal internalpartitioning wall means in the downstream end portion thereof withrespect to combustion gases as defined by cylindrical-form partitioningmeans 21 and catalyst means 22. There is further provided a centrallypositioned transverse partitioning member 23 at the juncture betweeninternal wall means 21 and catalyst means 22 such that the gases leavingthe burner means and the preheated gas inlet means at the burner end ofthe incinerator unit will be deflected initially to a heat exchangesection 24 encompassing catalyst means 22 such that there is a resultingradial inward flow to a central gas collecting zone 25 and the dischargeof a treated fume gas stream through passageway means 26, as defined bycylindrical wall means 27, to a gas outlet means at 28.

The embodiment of FIG. 4 also indicates that a plurality of tubularmembers 29 will be provided in the heat exchange section 24, with suchtubes extending between a transverse tube sheet 30 at the fume inlet endof the incinerator and a similar transverse tube sheet (not shown) whichwill be at the opposing end of the incinerator in a means similar to theembodiments of FlGS. l and 3. The multiplicity of tubes 29 will serve topass the contaminated air stream being introduced at inlet means 31 andfrom a gas distribution section 32 to the burner end of the incineratorunit to then pass in a reverse flow around a suitable burner means intoa central combustion section 33, ahead of transverse partitioning 23, tothen flow into the annular-form heat exchange section 24.

In connection with the embodiment of FIG. 4, it is to be noted thatvarious means may be provided for sup porting the internal partitioning21 as well as longitudinal cylinder form catalyst means 22 and that itis not intended to limit the incinerator unit to any one type ofconstruction. In this instance, spaced support bars or rod means 34 areshown as supporting cylindrical partitioning 21 and thus the internalend portions of the catalyst elements 22 while suitable support anglesat 35 and on transverse tube sheet 30 may be utilized to support theopposing ends of catalyst members 22. In FIG.

4 of the drawing, there is also an indication that catalyst 22comprisesa plurality of spaced segments which may be alternated withnon-perforate segments 22. In other words, it is not necessary that thecatalyst means be one continuous cylindrical form member as long as thecatalyst is provided in a gas pervious form between suitable supportplates and will, in turn, provide for the desired generally radial flowof gases therethrough in order to obtain substantially uniform flowthrough the entire internal portion of the incinerator unit.

Again, it is to be reiterated that the present improved form ofthermal-catalytic incinerator unit is con structed and arranged suchthat the unit may be operated either as a thermal conversion unit, acatalytic conversion unit, or as a combination unit. In the latterinstance, the catalyst will be utilized primarily as a second stageclean-up section while in a strictly thermal operation there can be theremoval of the one or more catalyst elements making up the catalystportion of the internal cylindrical-form partitioning wall.

It is to be recognized that each of the drawings are merely diagrammaticand that various modifications may be made with respect to the generalshapes and configurations of the housings and inlets or outlets, as wellas with respect to modifications in partitioning and baffling to effectthe desired flow for the contaminated gas stream and a radial flowthrough one or more catalyst elements. Also, it is not intended to limitthe invention to any one method of supporting, or positioning, for theone or more catalyst elements in combination with the internalcylinder-form partitioning means extending longitudinally to form theinterior sections of the incinerator housing. Still further, althoughnot shown in any of the drawings, there may be suitable insulationprovided around critical portions of the outer housing or around theheat exchange sections such that there may be an efficient retention ofheat within the entire incinerator unit. All of the burner means havebeen indicated as secondary air burners; however, other forms of burnermeans may well be used within the scope of the present invention so longas there is a suitable location of the burner means in order to effectthe proper mixing with the contaminated gas stream to be preheated, orto be thermally converted at such times as the incinerator will beoperating as a purely thermal incinerating device.

As a still further aspect, the burner means may be arranged other thanaxially with respect to the outer housing as long as the hot combustiongases from the burner are baffled or otherwise channeled to eventuallyflow into the central portion of the incinerator unit and then permitthe radial outward flow, or alternatively, the inward radial flow, withrespect to the catalyst portion of the partition so as to provide forthe uniform flow through the entire interior portion of the incinerator.

I claim as my invention:

1. A thermal-catalytic fume incineration unit, which comprises incombination, an elongated outer housing, internal cylindrical-formpartitioning spaced inwardly from the wall of said housing and extendingfor at least a portion of the internal length thereof to define anannular gas flow space therebetween and an internal combustion section,burner means positioned at the end of said housing and means todischarge hot burner gases axially into said combustion section, fumeinlet means into said housing and to said combustion section withpassageway means to the latter entirely surrounding said meansdischarging the hot burner gases, gas pervious catalyst means in atleast a peripheral portion of the down-stream section of saidcylindrical-form partitioning, and passageway means in interconnectionwith one face of the catalyst means from the combustion section wherebythe fume stream being treated may be passed in a radial type flowthrough said catalyst means, and treated gas outlet means from theopposing face of the latter and from said housing.

2. The incineration unit of claim 1 further characterized in that aninternal transverse partitioning means extends across said combustionsection whereby the fume stream and hot combustion gases will be passedradially inward through the gas pervious catalyst means.

3. The incineration unit of claim 1 further characterized in that saidinternal combustion section is open and coextensive with the interior ofsaid gas pervious catalyst means and the fume stream is passed radiallyoutwardly through said catalyst means.

4. The incineration unit of claim 1 further characterized in that saidtreated gas outlet means is at the same end of said housing as said fumeinlet means thereto whereby the treated gas stream from the internalcombustion section passes in substantially the same direction as the gasstream flow within the internal combustion section.

5. The incineration unit of claim 4 further characterized in that saidtreated gas outlet means from said heat exchange section and from saidhousing is peripherally adjacent the preheated gas section of saidhousing and at the opposite end thereof with respect to the gas streaminlet to said housing whereby there is a flow of the treated gas streamwithin said heat exchange section which is substantially opposite to thegas flow within'the internal combustion section of the unit.

1. A THERMAL-CATALYTIC FUME INCINERATION UNIT, WHICH COMPRISES INCOMBINATION, AN ELONGATED OUTER HOUSING, INTERNAL CYLINDRICAL-FORMPARTITIONING SPACED INWARDLY FROM THE WALL OF SAID HOUSING AND EXTENDINGFOR AT LEAST A PORTION OF THE INTERAL LENGTH THEREOF TO DEFINE ANANNULAR GAS FLOW SPACE THEREBETWEEN AND AN INTERNAL COMBUSTION SECTION,BURNER MEANS POSITIONED AT THE END OF SAID HOUSING AND MEANS TODISCHARGE HOT BURNER GASES AXIALLY INTO SAID COMBUSTION SECTION, FUMEINLET MEANS INTO SAID HOUSING AND TO SAID COMBUSTION SECTION WITHPASSAGEWAY MEANS TO THE LATTER ENTIRELY SURROUNDING SAID MEANSDISCHARGING THE HOT BURNER GASES, GAS PERVIOUS CATALYST MEANS IN ATLEAST A PERIPHERAL PORTION OF THE DOWN-STREAM SECTION OF SAIDCYLINDRICAL-FORM PARTITIONING, AND PASSAGEWAY MEANS IN INTERCONNECTIONWITH ONE FACE OF THE CATALYST MEANS FROM THE COMBUSTION SECTION WHEREBYTHE FUME STREAM BEING TREATED MAY BE PASSED IN A RADICAL TYPE FLOWTHROUGH SAID CATALYST MEANS, AND TREATED GAS OUTLET MEANS FROM THEOPPOSING FACE OF THE LATTER AND FROM SAID HOUSING.
 2. The incinerationunit of claim 1 further characterized in that an internal transversepartitioning means extends across said combustion section whereby thefume stream and hot combustion gases will be passed radially inwardthrough the gas pervious catalyst means.
 3. The incineration unit ofclaim 1 further characterized in that said internal combustion sectionis open and coextensive with the interior of said gas pervious catalystmeans and the fume stream is passed radially outwardly through saidcatalyst means.
 4. The incineration unit of claim 1 furthercharacterized in that said treated gas outlet means is at the same endof said housing as said fume inlet means thereto whereby the treated gasstream from the internal combustion section passes in substantially thesame direction as the gas stream flow within the internal combustionsection.
 5. The incineration unit of claim 4 further characterized inthat said treated gas outlet means from said heat exchange section andfrom said housing is peripherally adjacent the preheated gas section ofsaid housing and at the opposite end thereof with respect to the gasstream inlet to said housing whereby there is a flow of the treated gasstream within said heat exchange section which is substantially oppositeto the gas flow within the internal combustion section of the unit.